In a 1675 letter to his colleague Robert Hooke, Isaac Newton observed, "If I have seen further it is by standing on the shoulders of giants."  Three centuries later, this historic footnote became the theme for Project Apollo's farthest reach, America's final epic scientific expedition to the Moon that was the Apollo 17 mission in December 1972.  This final ambitious scientific exploration of the Moon saw both men and machines pushed close to their maximum human endurance and engineering design limits and represented not an end to sailing on the cosmic ocean, but a new beginning of an awakening of mankind's future destiny in space – as well as the end of the beginning that was the promise of Project Apollo.  The leader of this expedition was a most extraordinary American of indomitable spirit, vision, and enlightened understanding of our universe – an understanding that came from having made the mind-altering journey from the Earth to the Moon not just once, but twice.

As America and the world mourn the recent passing of retired U.S. Navy captain Eugene Andrew Cernan, we remember him as a man of many accolades to include true American patriot, distinguished U.S. Navy ROTC graduate of Purdue University and naval aviator, and distinguished Project Gemini and Apollo astronaut.  An American original, with the heart and soul of an explorer, Gene Cernan was fully prepared at the right time and place not only to live history, but also to make it.  To witness Captain Cernan's heartfelt interactions with humanity from all walks of life, or for those fortunate to have crossed paths with him on a personal level revealed a man with a big heart and a deep caring for others.  His joy, generosity of spirit, and passion for sharing his profound experiences provided a window into his soul.

Gene Cernan inspired several generations of young Americans to join the U.S. Navy to pursue the opportunity to follow in his footsteps.  Equally extraordinary was his great enthusiasm, humility, and ability to communicate to casual observers and laypersons the world over of his unique perspectives, emotions, and wonderment from his three complex space flight experiences and explorations.  Those who were fortunate to witness his journeys during Projects Gemini and Apollo never forgot the amazing accomplishments achieved – and the sacrifices he and his colleagues made to forge American pre-eminence in space.  He was a tireless champion for America's manned space program past, present, and future, emphasizing the strategic importance for maintaining our American leadership in manned space flight – and the urgent need to expand our human settlement of the Moon and beyond.

It was clear to all who crossed paths with him over the decades that he truly enjoyed the public role of "American astronaut," a glaring spotlight and crushing fame that could easily undermine individuals of a weaker personal constitution.  Carrying the American torch of liberty and technical achievement for much of his life, he truly made our nation and our world a better place because he was a part of it.  While each of his space missions originated as engineering test flights in the Cold War race to the Moon, which saw a free nation – not a Communist one – first land men on the Moon and return them safely to Earth, the final Apollo 17 "J" Mission was the last in the series dedicated purely to science.  With the hindsight of half a century, there should be no doubt that NASA leadership made the right decision to send Gene Cernan to the Moon twice.

In comparison with some of his more reserved space veteran colleagues, Captain Cernan was a storyteller extraordinaire.  At one Smithsonian National Air and Space Museum gathering in later years, he masterfully answered a young six- or seven-year-old boy's innocent question that he must have answered thousands of times previously under similar circumstances over the decades, with all the patience and joy as if he had heard the question for the first time: "Were you scared walking on the Moon?"  Cernan smiled and intently replied to the little boy that no, he was not scared – but he was apprehensive while walking on the Moon.  He proceeded to explain "apprehension": a kind of knowledge different from "fear," or being scared of the unknown.  This was the Gene Cernan that many knew and loved – and he never lost the common touch communicating his adventures and incredible experiences with others, no matter how simple or complex the questions posed to him. 

On another occasion, while visiting his adult daughter, then a public school teacher, America's most experienced lunar voyager greeted the youngsters born decades after Apollo, learning about space travel and fundamental principles of physics, rocket propulsion, and similar topics.  A young local adult news reporter was sent to cover his classroom visit.  She excitedly took the opportunity to ask her subject, "When will America return to the Moon?"  The old Apollo veteran looked at the reporter and then pointed over to the young children on the floor building their rocket and responded dryly, "Don't ask me.  Ask them."  This was the more somber side of Gene Cernan, who knew how to make an effective point.

By the time he commanded America's spectacular last lunar landing expedition, Apollo 17, Gene Cernan had the equivalent of a master's degree in geology and had exhaustively studied lunar geology for nine years, along with an intensive pre-flight survey of their landing site in the Moon's stunning Taurus-Littrow Valley on the southeastern edge of Mare Serenitatis.  Cernan and his Lunar Module pilot were a highly trained duo who worked exceedingly well together.  Sent on the ultimate geology field trip, their destination was the Taurus-Littrow Valley, ringed by mountains, which featured all kinds of tantalizing geologic mysteries and opportunities for discovery.

The second day of their human exploration of the surreal, breathtakingly beautiful valley, ringed by previously unseen vistas and silent ramparts towering above them, saw Cernan and Schmitt drive nearly 13 miles around the valley floor, at times out of sight of their Lunar Module, "Challenger."

At every turn, the two American explorers noted all kinds of diverse geology scattered about them and at their feet – even the soil granules glistened in the brilliant sunlight like fine precious gemstones of every color imaginable spread across the rugged terrain.  Mere photographs did not do justice to what their eyes were seeing.  Cernan wondered, do we stay here or press on and drive over the crest of the next hill?   What will we find there?  It was the greatest drive in the course of human history through a pristine, ancient wilderness with a small, jeweled blue planet hovering 11 degrees low over the horizon, hanging in a velvety black sky – a scene that defied the blinding lunar daylight and their more familiar earthly frame of reference.

Fortunately for America and the world, Captain Cernan never stopped talking about his incredible lunar experiences – including the amazing sights that his mind at times had difficulty processing.  He never stopped reminding Americans that our leadership in space is vital as we look to the future of human spaceflight and that for a brief period, that once optimistic, forward-looking, deep space-faring nation and people were we.  Only a bold explorer and an American original could  convey the wonderment and fascinating philosophical and descriptive details and emotions of traveling to, living, and working on the Moon. 

Godspeed, Captain Cernan, and thank you again for taking us along with you in spirit as you stood on the shoulders of giants.

The author is a former National Air and Space Museum docent and research assistant to Dr. Farouk El-Baz at the Center for Earth and Planetary Studies from 1976-79.  He has maintained a 40-year affiliation with NASM, which he helped open in July 1976.